33 results about "Arterial tree" patented technology

A method and system for imaging an artery contained in an arterial tree. A microprocessor generates a three-dimensional reconstruction of the arterial tree from two or more angiographic images obtained from different perspectives. The orientation of the axis of the artery in the arterial tree is then determined, and a perspective of the artery perpendicular to the axis of the artery is determined. A three dimensional reconstruction of the artery from angiographic images obtained from the determined perspective is then generated.

The present invention provides methods and apparatus for determining a dynamical property of the systemic or pulmonary arterial tree using long time scale information, i.e., information obtained from measurements over time scales greater than a single cardiac cycle. In one aspect, the invention provides a method and apparatus for monitoring cardiac output (CO) from a single blood pressure signal measurement obtained at any site in the systemic or pulmonary arterial tree or from any related measurement including, for example, fingertip photoplethysmography.According to the method the time constant of the arterial tree, defined to be the product of the total peripheral resistance (TPR) and the nearly constant arterial compliance, is determined by analyzing the long time scale variations (greater than a single cardiac cycle) in any of these blood pressure signals. Then, according to Ohm's law, a value proportional to CO may be determined from the ratio of the blood pressure signal to the estimated time constant. The proportional CO values derived from this method may be calibrated to absolute CO, if desired, with a single, absolute measure of CO (e.g., thermodilution). The present invention may be applied to invasive radial arterial blood pressure or pulmonary arterial blood pressure signals which are routinely measured in intensive care units and surgical suites or to noninvasively measured peripheral arterial blood pressure signals or related noninvasively measured signals in order to facilitate the clinical monitoring of CO as well as TPR.

A polyline tree representation of a coronary artery tree imaged in a volume data set is obtained, and its topology is extracted to give a topological representation indicating the relative positions of vessels in the tree. The topological representation is compared with a set of topological rules to find possible anatomical classifications for each vessel, and a set of candidate labeled polyline trees is generated by labeling the polyline tree with labels showing each combination of possible anatomical classifications. Each candidate labeled tree is filtered according to a set of geometric rules pertaining to spatial characteristics of vessels in arterial trees, and any labeled tree not satisfying the geometric rules is rejected A figure of merit is calculated for each remaining candidate by comparing features of the vessels measured from the polyline tree and from the volume data set with features of correctly classified vessels in other data sets to determine the probable correctness of the labeling of each candidate, and the candidate with the best figure of merit is selected as showing the proper classification of the vessels.

The invention provides a method and an apparatus for a continuous non-invasive and non-obstrusive monitoring of blood pressure. The method comprises the steps of: a) measuring the value (PW) of a Pulse Wave parameter, equal to or derived from the Pulse Wave Velocity (PWV) parameter of a segment of the arterial tree of a subject, b) measuring the value (CO) of the Cardiac Output parameter, and c) determining the value (BP) of the blood pressure that satisfiesB⁢⁢P=arg⁢⁢minBP⁢⁢d⁡(P⁢⁢W,⁢(C⁢⁢O,B⁢⁢P)),where PW is the value measured in step a), (CO, BP) corresponds to a predicted value of the Pulse Wave parameter computed according to a model of the segment of the arterial tree, the value (CO) of the Cardiac Output parameter measured in step b) and an hypothesized value of the blood pressure.

The methods and systems for estimating cardiac output and total peripheral resistance include observing arterial blood pressure waveforms to determine intra-beat and inter-beat variability in arterial blood pressure and estimating from the variability a time constant for a lumped parameter beat-to-beat averaged Windkessel model of the arterial tree. Uncalibrated cardiac output and uncalibrated total peripheral resistance may then be calculated from the time constant. Calibrated cardiac output and calibrated total peripheral resistance may be computed using calibration data, assuming an arterial compliance that is either constant or dependent on mean arterial blood pressure. The parameters of the arterial compliance may be estimated in a least-squares manner.

The methods and systems for estimating cardiac output and total peripheral resistance include observing arterial blood pressure waveforms to determine intra-beat and inter-beat variability in arterial blood pressure and estimating from the variability a time constant for a lumped parameter beat-to-beat averaged Windkessel model of the arterial tree. Uncalibrated cardiac output and uncalibrated total peripheral resistance may then be calculated from the time constant. Calibrated cardiac output and calibrated total peripheral resistance may be computed using calibration data, assuming an arterial compliance that is either constant or dependent on mean arterial blood pressure. The parameters of the arterial compliance may be estimated in a least-squares manner.

Embodiments relate to detecting coronary stenosis through spatio-temporal tracking. Aspects include extracting a coronary artery tree from each of a sequence of angiogram images, creating a mean artery tree from the extracted coronary artery trees, and projecting the mean artery tree back onto each of the sequence of angiogram images to recover a complete coronary artery tree for each of the sequence of angiogram images. Aspects also include extracting one or more tubular sections from each of the sequence of angiogram images, estimating an arterial width for each of the one or more tubular sections from each of the sequence of angiogram images, and creating a spatio-temporal surface from the arterial widths of the one or more tubular sections over a time spanned by the sequence of angiogram images. Aspects further include detecting a minimum in the spatio-temporal surface and determining if the minimum is indicative of stenosis.

A method for determining a cardiac function, comprising (i) determining base anatomical characteristics associated with the subject, (ii) determining pulse delay to a first body site (PD01) and a second body site (PD02) as a function of the anatomical characteristics, wherein the distance via the arterial tree from the aortic valve to the first body site (PD01) is different than the arterial tree distance from the aortic valve to the second body site (PD02), (iii) determining pulse wave velocity between the first body site and the second body site (PWV12), (iv) determining pulse wave velocity between the aortic valve and the first body site (PWV01) as a function of PWV12, and the anatomical characteristics; and (v) determining the pre-ejection period (PEP) as a function of PD01 and PWV01.

The disclosure relates to an image processing method for estimating a brain shift in a patient, the method involving: the processing of a three-dimensional image of the brain of a patient, acquired before a surgical operation, in order to obtain a reference cerebral arterial tree structure of the patient; the processing of three-dimensional images of the brain of the patient, acquired during the operation, in order to at least partially reconstitute a current cerebral arterial tree structure of the patient; the determination from the combination of the reference and current cerebral arterial tree structures, of a field of shift of the vascular tree representing the shift of the current vascular tree in relation to the reference vascular tree; the application of the determined field of shift of the vascular tree to a biomechanical model of the brain of the patient in order to estimate the brain shift of the patient; and the generation, from the estimated brain shift, of at least one image of the brain of the patient, in which the brain shift is compensated.

The systems and methods described herein enable reliable estimation of cardiovascular indices on real-time, non-invasive or minimally-invasive, and beat-to-beat basis. Cardiovascular indices which can be estimated include: stroke volume (SV), which being limited to, cardiac output (CO) and total peripheral resistance (TPR). In various embodiments, one or more of these indices are estimated continuously, on a beat-to-beat basis, using peripheral arterial blood pressure (ABP) waveforms and certain parameters derived from the peripheral ABP waveforms. The derived parameters are substantially insensitive to distortions of the ABP waveform arising from tapered arterial branches throughout the arterial tree. The methods describe herein can provide a more accurate and reliable estimate of hemodynamic parameters than existing techniques.

The invention discloses a method and a device for detecting the body's hemodynamic response in external counterpulsation therapy. The detection method includes: collecting physiological information of a sampler, and performing blood vessel and blood flow state data before and during external counterpulsation therapy. Acquisition; segment the arterial tree based on the arterial tree structure model, collect the length and radius data of each blood vessel segment of healthy volunteers, set the baseline reference value, and construct the geometric solution model of the arterial tree; calculate and set the boundary conditions, correction and calibration conditions, and Based on the pulse wave transmission theory and model, the flow rate and pressure pulse wave distribution at each position of the arterial tree are solved and calculated, and the blood perfusion and blood pressure levels of target blood vessel segments and organs before and during external counterpulsation treatment are calculated. The invention can non-invasively, real-time and effectively analyze the immediate hemodynamic effect of external counterpulsation intervention treatment, and solves the technical bottleneck that the current external counterpulsation therapy lacks an effective instant hemodynamic effect evaluation method.